This top uses bamboo as the main constituent in its fabric, although you wouldn’t really know that, as it has a pleasant softness against the skin, not unlike cotton (which makes up nearly a third). It is this cotton element that becomes apparent once you start to sweat. More moisture is held close to the skin than with rival base-layers, although it does evaporate. Odour isn’t a big problem for a use or two, although a couple of strenuous days does have it starting to pong. The tight fit is good, and there is a fair amount of stretch in the fabric too, without looking overly sporty or riding up too much. The stretch also enables you to pull the sleeves up when it’s warmer and keeps them up. At this price it’s something of a bargain.